The present invention relates to chairs, in particular to chairs having a flexible back support.
Chairs, such as stackable banquet chairs, are well known in the prior art. They may be designed to stack one atop another when not in use so as to reduce the necessary storage space. The chairs may have a padded seat cushion and a padded back support cushion. The back support is at an angle to the seat cushion and usually is essentially non-flexible.
Numerous attempts have been made to improve the comfort level of chair occupants. For example, there have been various attempts at providing stackable chairs with flexible backs. That is, there have been designs that allow the back support portion of the chair to flex with respect to the seat cushion, thereby allowing an occupant to recline. However, such efforts have often led to complicated mechanisms that would be expensive to manufacture, or less comfortable chairs, for example chairs in which only part of the back support flexes. There is a need for a simple, comfortable, and reliable chair design.
U.S. Pat. No. 2,587,822 to Coming describes a resiliently mounted chair back. However, the described chairs include soft yieldable materials that may weaken the structure. U.S. Pat. No. 3,544,160 to Karasick describes a seat back positioning system, having a relatively complex arrangement having a moving rod.
U.S. Pat. No. 4,084,850 to Ambasz describes a chair with a back connected to a seat support by an articulating connector. U.S. Pat. No. 4,333,683, also to Ambasz, describes a chair with a tilting upper back portion. The disclosed chair has a unitary seat and lower back portion. However, it can be more comfortable to have a back that tilts in its entirety.
U.S. Pat. Nos. 4,603,904 and 4,869,552 to Tolleson et al. describe a chair with a flexible backrest. The seat frame includes a pair of upstanding, spaced apart members protruding above the level of the seat. U.S. Pat. No. 5,039,163, also to Tolleson et al., describes a flexible backrest assembly for a chair. U.S. Pat. No. 4,938,532 to Burgess describes a chair having a torsion bar.
U.S. Pat. No. 6,406,096 to Barile Sr. describes a seat spring system to provide a flexible spring backrest frame. U.S. Pat. No. 6,471,293 to Ware et al. describes a stackable chair with a flexible back support. U.S. Pat. No. 6,533,352 to Glass et al. describes a chair having a reclining backrest, the chair having a pretensioned spring.
However, the prior art fails to offer a chair providing the comfort of a flexible back support using a simplified frame construction.
A chair comprises a seat support assembly including a seat support, the seat support assembly being adapted to stand on a surface so as to provide the seat support at a suitable height for a person to sit on, and a back support assembly, including a back frame member and a back support. In one embodiment, the back frame member has a curved middle portion substantially in the plane of the back support, and first and second end portions substantially in the plane of the seat support. The back frame member is flexibly interconnected to the seat support assembly by a first spring flexibly interconnecting the first end portion of the back frame member and the seat support assembly; and a second spring flexibly interconnecting the second end portion of the back frame and the seat support assembly.